ATLANTA (AP) — Police are searching for at least one armed suspect in connection with the killing of the owner of a gun range in Georgia and his wife and grandson, authorities said Saturday.

The Grantville Police Department said via Facebook that the robbery occurred on April 8. When officers arrived at the scene around 8 p.m., they found the bodies of the owner of Lock Stock & Barrel Shooting Range, along with his wife and grandson.

When the county coroner, Richard Hawk, arrived he learned that those remains were of his parents and son. Grantville Police identified the victims as the gun range owner, Thomas Hawk, 75; his wife, Evelyn, 75; and their grandson, Luke, 17.

Police Chief Steve Whitlock said the Hawk family was well-known and well-respected in their small, tight-knit community. The Hawks had operated Lock Stock & Barrel for nearly 30 years. Their grandson was on spring break, helping his grandparents at the shop.

“This is just a shock to everybody in the community,” Whitlock told The Associated Press. “We’re trying to do the best that we can to figure this out.”

Whitlock said investigators believe the robbery and shooting happened around 5:30 p.m. Friday, when the range closes typically. He said Hawk’s son, Richard, came by the business and was the person who found the victims.

There are no suspects as of early Saturday, and no arrests have been made, he said. However, investigators said that as many as 40 guns and the range’s surveillance cameras were also stolen.

The Georgia Bureau of Investigation is investigating but referred all inquiries to Grantville Police when contacted Saturday. The Bureau of Alcohol, Tobacco, Firearms and Explosives was also called in due to the amount of weapons taken. Whitlock said he’s grateful for the help from other law enforcement agencies in the investigation.

“We’re just a small town, 12 officers. I’ve been here eight years and have never had to investigate anything like this. It’s been kind of hard on us. The crime rate is really, really low,” he said.

A reward of $15,000 has been posted for information leading to the arrest and conviction of the killer or killers in the case, according to the ATF Atlanta office’s Twitter feed.

“ATF and our law enforcement partners will work tirelessly to bring the killer(s) to justice,” ATF Atlanta Field Division Special Agent in Charge Benjamin P. Gibbons said in a statement. “The brutality of these senseless murders along with the fact that these killer(s) have acquired additional firearms makes solving this case our top priority.”

A message left with the ATF office in Atlanta was not immediately returned.

Police are asking any witnesses to come forward. However, Whitlock said they don’t have any video evidence to work with right now.

“Anyone having driven by the shooting range during the time frame of 530pm to 630 pm that may have seen vehicles other than a white Ford dually truck and a black Ford expedition are asked to contact the police department,” Grantville police said in their Facebook statement.

The shooting range is in rural Coweta County, about 50 miles southeast of Atlanta.

Coweta County Sheriff Lenn Wood said in a statement on Facebook that the entire community was forever broken by the “senseless and tragic” killings of the Hawk family members.

“I am also fervently praying that God will use our law enforcement community and the Coweta Community,” he said, “to bring justice swiftly.”